Good quality water with a salinity of below 500 grains per gallon is required for the washing of gypsum, a minimum supply of 1,500 gallons per hour being needed. In the Salt Lake District supplies of probably not more than 100 to 200 gallons per hour were reported but the full extent of the aquifer and yields were insufficiently known. In a previous report (Hyd. 864, Report Book 50/11) drilling of 15 bores was recommended. Since the costs of pumping or carting water obtained from bores on sites 12 to 15 would be prohibitive, these sites were not tested. In the course of drilling it appeared that further information east of Salt Lake was required and bores 12-13 were drilled on the sites 6A and 6B. Before the whole drilling programme was completed, pump tests were carried out on bores 6, 9 and 10. The drilling programme was started on the 18th January, 1960 and completed on 23rd May, 1960. It was interrupted twice while bores were drilled for private landholders in the district. These provided valuable additional information.